Method and device for adapting the video content decoded from elementary streams to the characteristics of a display

ABSTRACT

The present disclosure relates to a method and device for adapting a video content decoded from elementary streams to the characteristics of a display from at least one type of metadata giving information regarding said elementary streams. Such a method comprises:—obtaining ( 102 ) an additional information (HDR DESCR.) indicating the presence of one particular type of metadata;—determining if said video content decoded from elementary streams is display-able on said display ( 11 ) from said additional information (HDR DESCR.) and the characteristics of the display (EDID); and—if said video content decoded from elementary streams is determined as being displayable, selecting ( 105 ) a process from said additional information and the characteristics of the display and adapting ( 106 ) the video content according to the selected process.

This application is a national stage application under 35 U.S.C. § 371of International Application PCT/EP2016/076707, filed Nov. 4, 2016,which was published in accordance with PCT Article 21(2) on May 18,2017, in English, and which claims the benefit of European PatentApplication No. 15306777.2, filed Nov. 9, 2015.

1. FIELD

The present disclosure generally relates to picture/video encoding anddecoding. Particularly, but not exclusively, the technical field of thepresent disclosure relates to delivering a High Dynamic Range (HDR)content on displays with different capabilities.

2. BACKGROUND

The present section is intended to introduce the reader to variousaspects of art, which may be related to various aspects of the presentprinciples that are described and/or claimed below. This discussion isbelieved to be helpful in providing the reader with backgroundinformation to facilitate a better understanding of the various aspectsof the present principles. Accordingly, it should be understood thatthese statements are to be read in this light, and not as admissions ofprior art.

The capture and display of image content, whether static pictures orvideos, with a dynamic range that approaches real scenes has been along-term challenge.

Actually, human vision has wide latitude for scene brightness, and hasmultiple adaptation mechanisms that provide an automatic gain to thehuman visual system. Notably, the brightness range that people can seeis much greater than the available contrast range of most currentlyexisting displays.

In an attempt to offer display of contents meeting the requirements ofhuman vision, High Dynamic Range (HDR) images have recently beenspecified and defined, which include higher peak luminance, lowerminimum luminance, greater contrast range, as compared to StandardDynamic Range (SDR) images. In other words, HDR images offer increasedshadow and highlight detail over SDR images, namely brighter whites,darker blacks, and brighter colors that better match images we see inthe real world.

As is well known, a picture, whether of a HDR or SDR type, may berepresented by one or several arrays of samples (aka pixel values) in aspecific encoding format, which specifies all information relative tothese pixel values and all information which may be used by a displayand/or any other device to decode and/or display this picture. The sameapplies for video contents. In the following, the term “image content”will be used to cover both pictures and video contents.

An image content usually comprises at least one component, in the shapeof a first array of samples, usually a luma (or luminance) component,and, possibly, at least one other component, in the shape of at leastone other array of samples, usually a color component. Or, equivalently,the same information may also be represented by a set of arrays of colorsamples, such as the traditional tri-chromatic RGB representation.

A pixel value is represented by a vector of C values, where C is thenumber of components. Each value of a vector is represented with anumber of bits, which defines a maximal dynamic range of the pixelvalues.

It is expected that broadcasters and distributors of image contents willfrequently need to convert between SDR and HDR content to supportdelivery to all possible outlets and devices. This may be the case,notably, for the conversion from HDR content to layered content whichallows backwards compatibility with SDR distribution and displaysystems. It may also be the case for interoperation of HDR signals withHDR displays having less peak white capability than the source.

Displays, image processors, up/down color convertors will all need todetect the HDR encoding and colorimetry in use to correctly process anddisplay the signal.

In order to ease such processing, some Standards DevelopingOrganizations (SDO) have specified a set of metadata information to beassociated with the HDR (High Dynamic Range) coded video streams. Thepurpose of these metadata is to facilitate the adaptation (e.g.HDR-to-SDR or HDR-to-HDR remapping) or the interpretation of thereconstructed HDR pictures to the current display characteristics.

Such HDR metadata mainly comprise static metadata on the one hand, anddynamic or content-dependent metadata, on the other hand, the latterbeing defined as metadata that can vary dynamically throughout thesource content (i.e. can change per scene inside the same sequence).

They comprise, for example:

Mastering Display Color Volume information (as described for example inSMPTE Standard ST 2086:2014, “Mastering Display Color Volume MetadataSupporting High Luminance and Wide Color Gamut Images”, CEA Standard“HDR Static Metadata Extensions CEA-861.3 January 2015 and ITU-T H.265(10/2014)): such static metadata are included with mastered HDR contentto convey the color volume of the mastering display and the luminance ofthe content. This is described by the chromaticity of the red, green andblue display primaries and white point of the mastering display, plusits black level and peak luminance level. In other words, such staticmetadata describe the actual HDR color volume of the mastering displayused to create the image content in order to guide the contentadaptation (ex: color volume remapping) towards the displaycharacteristics.

Color Remapping Information (CRI) (as described in ITU-T H.265 (10/2014)and SMPTE Standard ST 2094-30 in ballot): a dynamic metadata representedby a parametric model function that operates a color volume remappingtransformation of the HDR pictures to create SDR (represented with astandardized format) pictures. Such dynamic metadata conveyframe-by-frame or scene-by-scene Color Remapping Information, which willenable color transformation to be variable along the contenttimeline.—Content Light Level information (as described in CEA Standard“HDR Static Metadata Extensions CEA-861.3 January 2015 and ITU-T H.265(04/2015)): the minimum and averaged maximum luminance values tore-scale the HDR content to the HDR display capabilities (ex: powerconsumption).

HDR compatibility (as described in ITU-T H.265 (04/2015) and by M.Naccari, A. Cotton, S. Schwarz, M. Pindoria, M. Mrak, T. Borer (BBC), in“High dynamic range compatibility information SEI message,”): suchmetadata indicate that the content can be displayed on HDR or SDRdisplays, with an appropriate (pre-defined) post-processing.

These different HDR-related metadata types can be used by a receiver incharge of decoding the receiver encoded video content, for example theIntegrated Receiver Device (IRD), to adapt the reconstructed HDRpictures to the display characteristics, for example to the displaycurrently connected to the IRD.

Actually, when source content mastered with HDR is transformed forpresentation on a display having a smaller color volume such as a SDRdisplay, the color transformation process can be optimized through theuse of these content-dependent, dynamic color transform metadata.

As the content characteristics change from scene to scene, the optimaltransform processing that best reproduces the content creators' artisticintent can change. For example, the color volume transformationparameters used for a very dark scene could be quite different fromthose used for a very bright scene.

Hence, the transforms can be represented as metadata synchronized withthe frames of one master. The metadata can be captured or generated aspart of the mastering process, when images are creatively approved, andlater applied in media conversions during the distribution stage.

More precisely, the IRD, which may be part of a set-top-box for example,or integrated in a TV set, may use one or combine several of thesemetadata to perform the adaptation of the decoded HDR pictures to thetargeted display capabilities (e.g. SDR, HDR, WCG (for Wide ColorGamut). . .), depending on the Content Adaptation (CA) methodimplemented in the IRD. Actually, some decoding devices will only usestatic metadata, such as the so-called Mastering Display Color VolumeInformation, to operate a remapping from the HDR content into a SDRimage content. Some others will use one or several dynamic metadata toperform a more complex conversion from the HDR color volume into a colorvolume adapted to the display characteristics.

Moreover, while some decoding devices support several Content Adaptationmethods and may choose the most appropriate one depending on theavailable metadata, some others only support one of them.

As a consequence, if the metadata corresponding to the implementedmethod, and needed by the decoding device, is not present in theElementary Streams associated to the image content, then the adaptationof the decoded images to the display features is not possible or may beincorrect.

Moreover, for the time being, and as mentioned above, such metadata areembedded in the Elementary Streams (ES) associated to the encoded imagecontent. Actually, it must be recalled that images are encoded by acodec (as defined for example in MPEG-AVC/H.264 standard or MPEG-HEVC/H.265 standard) into an Elementary Stream (ES). This Elementary Stream isthen encapsulated into a transport layer, in order to be broadcasted ordistributed. There are several ways of encapsulating the ES into atransport layer, depending on the targeted application, and thecorresponding standard:

-   -   MPEG-2 Transport, for broadcasting applications (traditional TV,        mobile, network IPTV);    -   RTP, for video streaming applications on the Internet (Internet

Protocol);

-   -   MPEG-DASH, which relies on the ISO Base Media File Format        standard, and which may be used for conversational services,        IPTV, or Video-on-demand applications;    -   MPEG-2 Systems, for storage and download applications, such as        recording the image content on a DVD or a Blu-ray disc.        To access information on the presence of HDR metadata or HDR        features encoded into the elementary stream (ES, coded video        layer), the decoding device, such as the IRD, must hence first        select the right multiplex, next decode the transport layer        (TS), and next start decoding the Elementary Streams, without        knowing whether the metadata it requires for adapting the        decoded content to the display characteristics are, or not,        present in the ES. This is both time and power consuming.

Another drawback of this prior art technique lies in the fact that thereis no guarantee that, if available, the metadata will be present for theentire sequence or program.

Actually, some video programs are built thanks to splicing techniques,which may consist in cutting some video sequences from a movie forexample, and inserting between two cut parts a video sequencecorresponding to some advertisement. It is possible that thecorresponding stream will comprise metadata in the parts correspondingto some movie scenes, but not in the ad video sequence.

There is no way, for the decoding device, to know whether or not themetadata will be available for the whole duration of the video programor only for parts of it.

There is therefore a need for a technique allowing to overcome at leastsome of these drawbacks.

3. SUMMARY

The following presents a simplified summary of the present disclosure inorder to provide a basic understanding of some of its aspects. Thissummary is not an extensive overview of the present disclosure. It isnot intended to identify key or critical elements of the presentdisclosure. The following summary merely presents some aspects of thepresent disclosure in a simplified form as a prelude to the moredetailed description provided below.

According to an aspect of the present disclosure, a signal is provided,having at least one type of metadata giving information regardingelementary streams of an encoded video content. Such a signal isformatted to comprise an additional information indicating the presenceof at least one particular type of said metadata.

Hence, the present disclosure relies on a novel and inventive approachof the encoding of video signals, which comprises adding an additionalinformation within the signal representative of a video content, inorder to inform a receiver on the presence of one or several types ofmetadata within the signal. It is no longer necessary for a receiver tostart decoding the elementary streams in order to determine whether ornot some types of metadata are available within theses streams.Moreover, the receiver can directly know whether or not it will be ableto adapt the decoded video content to the characteristics of a displayto which it is connected, as a function of the available types ofmetadata, as indicated by this additional information. Such a techniqueallows saving both time and power consumption, as compared to prior arttechniques.

According to another aspect, said additional information also indicatesif said at least one particular type of said metadata is present withinsaid signal for a whole duration of said encoded video content. Areceiver of said signal can hence directly know whether the metadataneeded for adapting the decoded video content to the characteristics ofa display to which it is connected will be available for the wholeduration of the video sequence or program, or whether it will have tomodify or halt such adaptation during the video sequence. According toyet another aspect, said additional information also comprises at leastpart of said metadata. This is particularly advantageous for staticmetadata, for which part or full metadata information can be directlyavailable within the additional information, in order to help thereceiver choose which content adaptation method to use. According to afurther aspect, when said at least one particular type of said metadatabelongs to a set of dynamic metadata, said additional informationcomprises a first refresh information belonging to the group comprising:

a maximal dynamic metadata refresh rate;

a minimal time interval after which said dynamic metadata will berefreshed.

According to a further aspect, when said at least one particular type ofsaid metadata belongs to a set of dynamic metadata, said additionalinformation comprises a second refresh information belonging to thegroup comprising:

a minimal dynamic metadata refresh rate;

a maximal time interval after which said dynamic metadata will berefreshed.

Information on the metadata refresh rate are useful for the receiver ofsaid signal, in order to know when it will be able to start decoding thevideo content on the basis of refreshed metadata. This may beinteresting for example for a broadcasted video content, when a userdecides to switch from a TV channel to another.

According to an aspect of the present disclosure, said additionalinformation is present in a transport stream of said signal.

Hence, the receiver can directly access the information, without havingto decode the elementary streams which are encapsulated within saidtransport stream.

According to a further aspect, said encoded video content is a HighDynamic Range video content, and said metadata are High Dynamic Rangemetadata.

According to another aspect of the present disclosure, a method foradapting a video content decoded from elementary streams to thecharacteristics of a display from at least one type of metadata givinginformation regarding said elementary streams is provided. Such a methodcomprises:

obtaining an additional information indicating the presence of oneparticular type of metadata;

determining if said video content decoded from elementary streams isdisplayable on said display from said additional information and thecharacteristics of the display; and

if said video content decoded from elementary streams is determined asbeing displayable, selecting a process from said additional informationand the characteristics of the display and adapting the video contentaccording to the selected process.

Hence, a receiver of encoded video elementary streams may determinequickly and easily if the received content will be displayable,depending on the characteristics of the display and on the availablemetadata, and may select an appropriate content adaptation process, forexample for remapping an HDR content as a function of the colorimetricfeatures supported by the display.

According to another aspect, said additional information also indicatesif said at least one particular type of metadata is present within saidsignal for a whole duration of said video elementary streams.

According to other of its aspects, the present disclosure relates to adevice comprising a processor configured to implement the above method,a computer program product comprising program code instructions toexecute the steps of the above method when this program is executed on acomputer, a processor readable medium having stored therein instructionsfor causing a processor to perform at least the steps of the abovemethod, and a non-transitory storage medium carrying instructions ofprogram code for executing steps of the above method when said programis executed on a computing device.

The specific nature of the present principles as well as other objects,advantages, features and uses of the present principles will becomeevident from the following description of examples taken in conjunctionwith the accompanying drawings.

4. BRIEF DESCRIPTION OF DRAWINGS

The present disclosure can be better understood with reference to thefollowing description and drawings, given by way of example and notlimiting the scope of protection, and in which:

FIG. 1 shows a diagram of the steps of a method for adapting the contentof video elementary streams in accordance with an embodiment of thepresent disclosure;

FIG. 2 shows an example of an architecture of a device in accordancewith an embodiment of the present disclosure;

FIG. 3 shows the syntax of a signal in accordance with an embodiment ofthe present disclosure; and

FIG. 4 illustrates the tree structure of a multiplex stream carrying thevideo elementary streams adapted according to the method of FIG. 1 .

Similar or same elements are referenced with the same reference numbers.

5. DESCRIPTION OF EXAMPLE OF THE PRESENT PRINCIPLES

The present principles will be described more fully hereinafter withreference to the accompanying figures, in which examples of the presentprinciples are shown. The present principles may, however, be embodiedin many alternate forms and should not be construed as limited to theexamples set forth herein. Accordingly, while the present principles aresusceptible to various modifications and alternative forms, specificexamples thereof are shown by way of examples in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the present principles to the particularforms disclosed, but on the contrary, the disclosure is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present principles as defined by the claims.

The terminology used herein is for the purpose of describing particularexamples only and is not intended to be limiting of the presentprinciples. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises”, “comprising,” “includes” and/or “including” when used inthis specification, specify the presence of stated features, integers,steps, operations, elements, and/or components but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof. Moreover, whenan element is referred to as being “responsive” or “connected” toanother element, it can be directly responsive or connected to the otherelement, or intervening elements may be present. In contrast, when anelement is referred to as being “directly responsive” or “directlyconnected” to other element, there are no intervening elements present.As used herein the term “and/or” includes any and all combinations ofone or more of the associated listed items and may be abbreviated as“/”.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement without departing from the teachings of the present principles.

Although some of the diagrams include arrows on communication paths toshow a primary direction of communication, it is to be understood thatcommunication may occur in the opposite direction to the depictedarrows.

Some examples are described with regard to block diagrams andoperational flowcharts in which each block represents a circuit element,module, or portion of code which comprises one or more executableinstructions for implementing the specified logical function(s). Itshould also be noted that in other implementations, the function(s)noted in the blocks may occur out of the order noted. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently or the blocks may sometimes be executed in the reverseorder, depending on the functionality involved.

Reference herein to “in accordance with an example” or “in an example”means that a particular feature, structure, or characteristic describedin connection with the example can be included in at least oneimplementation of the present principles. The appearances of the phrasein accordance with an example” or “in an example” in various places inthe specification are not necessarily all referring to the same example,nor are separate or alternative examples necessarily mutually exclusiveof other examples.

Reference numerals appearing in the claims are by way of illustrationonly and shall have no limiting effect on the scope of the claims.

While not explicitly described, the present examples and variants may beemployed in any combination or sub-combination.

The present principles are described for encoding/decoding/adaptingvideo elementary streams representing a picture or a group of picturesor a whole sequence of pictures.

In the following, the present disclosure will be described in closerdetail in relation to a specific embodiment, in which the features ofthe present disclosure are applied to High Dynamic Range (HDR) ContentAdaptation selection process and HDR metadata signaling forTransport-Streams (TS).

As described previously in relation to the known prior art techniques,there is no information, in the transport stream associated to anencoded video content, relating to the presence of HDR metadata, whichcould be useful for receivers. As a consequence, a receiver/decoderrequires parsing a HDR coded stream before making decision on whetherthe decoded content should be adapted to targeted displaycharacteristics, prior to carriage to the targeted display. Those stepsimply resource consumption (decoding portions of Elementary Streams) andlook-ahead (inspecting what is in the stream).

The present disclosure consists in specifying an High Dynamic Range(HDR) metadata descriptor that enables knowing accessible HDR specificfeatures through an HDR Elementary Stream (ES). This has importance toadapt or interpret coded video when considering the whole consumer endchain such as receiver, decoder, renderer elements.

For instance, it allows having information about the presence ofHDR-to-SDR remapping metadata in the ES, for its full duration. Itfacilitates and simplifies the retrieval of this information, withoutrequiring to parse the ES itself. In that way, the receiver, for examplethe IRD, can know in advance whether the stream will be decodable anddisplayable (possibly taking into account adaptation capability of thereceiver) with the display connected to the Integrated Receiver Decoder(IRD) e.g. a STB (Set-Top-Box). Moreover, the receiver can also choosewhich Content Adaptation model to use, to adapt the decoded videocontent to the display characteristics.

FIG. 1 illustrates the main steps of a method for adapting a videocontent decoded from video elementary streams to the characteristics ofa display according to an embodiment of the present disclosure.

A receiver RX 10 is connected to a display 11. For example, the receiverRX 10 is an IRD integrated in a TV set 11, or is part of a set-top box,connected through an HDMI link to a display 11.

The receiver RX 10 receives a multiplex stream MX 1, corresponding to achannel modulation, as illustrated for example by FIG. 4 . Such amultiplex stream MX 1 has a tree structure 43, with, at a first level, atransport layer 41, in which are encapsulated Elementary Streams 42,corresponding to the encoded video content. Each Elementary Stream isassociated to an identifier, which may for example correspond to a TVchannel. Hence, in the example of FIG. 4 , a first signal Multiplex 0carries the Elementary Streams associated to identifiers pid_0, pid_1and pid_2, while a second signal Multiplex 1 carries the ElementaryStreams associated to identifiers pid_3 and pid_4.

The receiver MX 1 demultiplexes the multiplex stream MX 1 at step 101,and then parses the Transport Stream TS 41 at step 102. It hence obtainsan additional information HDR DESCR. indicating the presence of one orseveral particular types of metadata in the transport stream TS 41. Suchadditional information HDR DESCR. are used, in conjunction withinformation EDID relating to the characteristics of the display 11, todetermine if the decoded pictures from the received video elementarystreams are displayable on the display 11, at step CA SELEC 105. TheEDID information are received from a display control module DISP.CTRL111 and comprise notably the display supported formats and the displaycharacteristics. By comparing such EDID information with the metadataavailable in the multiplex stream MX 1, the receiver RX 1 may decide, atstep 105, which Content Adaptation method it should use to adapt thedecoded video content to the display characteristics, if the videoelementary streams are indeed determined as being displayable.

Once the Content Adaptation process is selected, the receiver RX 10adapts the video content decoded from the elementary streams accordingto the selected process at step CA 106. The video content decoded fromthe elementary streams DEC. PIC. are obtained after a step 104 of VideoES Decoding, resulting from a step 103 in which the Elementary Streams42 encapsulated in the Transport Stream 41 have been parsed. Theadapted, or remapped pictures REMAP. PICT. are sent to the display 11 inorder to be rendered at step 110 DISP. RENDER.

Thus, the HDR_descriptor is used by the IRD for:

Determination by IRD whether the HDR video is (correctly) displayable onthe connected display thanks to EDID information (display supportedformats) and HDR_descriptor information.

If HDR content is displayable, selection of the appropriate ContentAdaptation method given the display capabilities.

It must be noted that only the TS layer 41 is parsed, not the ES 42.

According to an embodiment of the present disclosure, addition of adescriptor in the TS (Transport Stream) layer 41 signals the presence ofone particular type of HDR metadata or feature. It may also signal ifthis information is present for the whole program or sequence duration.

An example of syntax of such a descriptor HDR DESCR. (also calledadditional information in the present document), which is carried by asignal F, is presented in Table 1.

TABLE 1 Example of HDR metadata descriptor. Syntax No. Of bits MnemonicHEVC_HDR_descriptor( ) {mastering_display_colour_volume_info_present_flag 1 bslbfcolour_remapping_info_present_flag 1 bslbfcontent_light_level_info_present_flag 1 bslbfhdr_compatibility_info_flag 1 bslbf reserved 4 bslbf ... }

As may be observed in Table 1, the descriptor comprises flags indicatingthe presence of four different types of metadata, namely:

-   -   Color Remapping Information (CRI);    -   Mastering Display Color Volume Information;    -   Content Light Level Information;    -   HDR Compatibility.

When the value of the flag is set at “1”, it indicates that thecorresponding type of metadata is present for the whole duration of theencoded video stream, or the whole program.

According to an embodiment, part or full static metadata informationcould be available in the descriptor as given in example with the“Mastering Display Colour Volume information” in Table 2.

TABLE 2 Example of HDR metadata descriptor. Syntax No. Of bits MnemonicHEVC_HDR_descriptor( ) {mastering_display_colour_volume_info_present_flag 1 bslbfcolour_remapping_info_present_flag 1 bslbfcontent_light_level_info_present_flag 1 bslbfhdr_compatibility_info_flag 1 bslbf reserved 4 bslbf if(mastering_display_colour_volume_info_present_flag ) { 16 bslbf for( c =0; c < 3; c++ ) { 16 bslbf display_primaries_x[ c ] display_primaries_y[c ] } white_point_x 16 bslbf white_point_y 16 bslbfmax_display_mastering_luminance 32 bslbf min_display_mastering_luminance32 bslbf }The features of the corresponding metadata, namely the associatedcolorimetric primaries, the white points and the minimum and maximumdisplay mastering luminance are directly available in the descriptor HDRDESCR. in the transport stream 41.

According to an embodiment, the maximal dynamic metadata refresh rate orminimal period is signaled. It indicates the minimum interval thedynamic metadata are being refreshed (example in Table 3). Thisinformation may be expressed in number of reference clock rate number ornumber of ticks (ex: 90 KHz).

TABLE 3 Example of HDR metadata descriptor with dynamic metadata refreshrate. Syntax No. Of bits Mnemonic HEVC_HDR_descriptor( ) {mastering_display_colour_volume_info_present_flag 1 bslbfcolour_remapping_info_present_flag 1 bslbfcontent_light_level_info_present_flag 1 bslbfhdr_compatibility_info_flag 1 bslbf reserved 4 bslbf if (colour_remapping_info_present_flag ) {max_colour_remapping_info_refresh_rate 32 bslbf } }

According to an embodiment, the minimal dynamic metadata refresh rate ormaximal period is signaled. It indicates the maximum interval thedynamic metadata are being refreshed (example in Table 4). Thisinformation may be expressed in number of reference clock rate number ornumber of ticks (ex: 90 KHz) or number of ES video frame rate.

TABLE 4 Example of HDR metadata descriptor with dynamic metadata refreshrate. Syntax No. Of bits Mnemonic HEVC_HDR_descriptor( ) {mastering_display_colour_volume_info_present_flag 1 bslbfcolour_remapping_info_present_flag 1 bslbfcontent_light_level_info_present_flag 1 bslbfhdr_compatibility_info_flag 1 bslbf reserved 4 bslbf if (colour_remapping_info_present_flag ) {min_colour_remapping_info_refresh_rate 32 bslbf } }

According to an embodiment, the remapped (colour_remapping_info) signalcharacteristic is signaled. It will be used by the IRD to know (choose)which format to be sent to the display, and/or to know if it issupported by the display.

TABLE 5 Example of HDR metadata descriptor with dynamic metadata refreshrate. Syntax No. Of bits Mnemonic HEVC_HDR_descriptor( ) {mastering_display_colour_volume_info_present_flag 1 bslbfcolour_remapping_info_present_flag 1 bslbfcontent_light_level_info_present_flag 1 bslbfhdr_compatibility_info_flag 1 bslbf reserved 4 bslbf if (colour_remapping_info_present_flag || hdr_compatibility_info_flag ) { 8bslbf colour_target_primaries 8 bslbf colour_target_transfer_function 8bslbf colour_target_matrix_coefficients } }A variant to the example of table 5 is provided below:

Syntax No. Of bits Mnemonic HEVC_HDR_descriptor( ) {mastering_display_colour_volume_info_present_flag 1 bslbfcolour_remapping_info_present_flag 1 bslbfcontent_light_level_info_present_flag 1 bslbfhdr_compatibility_info_flag 1 bslbf transfer_function_info_flag 1 bslbfcolor_info_present_flag 1 reserved 2 bslbf if (transfer_function_info_flag ) { bslbf colour_target_transfer_function 8bslbf } 8 if ( color_info_present_flag ) { 8 colour_target_primariescolour_target_matrix_coefficients } }The present disclosure thus provides several advantages over prior arttechniques:

-   -   The IRD RX 10 has access to the information of the presence of        some particular type of HDR static and dynamic metadata at a        high level (TS 41).    -   The IRD RX 10 has knowledge whether the metadata will be present        for all the duration of the program/sequence.    -   The IRD RX 10 doesn't need to parse the ES (42) anymore, but        only the TS (41), to know if it can display the HDR pictures        correctly.

In that way, the IRD RX 10 can give this information to the UserInterface (or to the content adaptation selection module) to warn aboutthe possibly full support (or not) of the HDR rendering, depending onits implemented post-processing (ex: color volume mapping) and dependingon the connected display characteristics via ED ID.

Additionally, it can select the appropriate (among the ones implementedin the IRD RX 10) content adaptation model.

On FIG. 1 , the modules are functional units, which may or not be inrelation with distinguishable physical units. For example, these modulesor some of them may be brought together in a unique component orcircuit, or contribute to functionalities of a software. A contrario,some modules may potentially be composed of separate physical entities.The apparatus which are compatible with the present principles areimplemented using either pure hardware, for example using dedicatedhardware such ASIC or FPGA or VLSI, respectively «Application SpecificIntegrated Circuit», «Field-Programmable Gate Array », «Very Large ScaleIntegration », or from several integrated electronic components embeddedin a device or from a blend of hardware and software components.

FIG. 2 represents an exemplary architecture of a device 20 which may beconfigured to implement a method described in relation with FIG. 1 .

Device 20 comprises following elements that are linked together by adata and address bus 21:

-   -   a microprocessor 22 (or CPU), which is, for example, a DSP (or        Digital Signal Processor);    -   a ROM (or Read Only Memory) 23;    -   a RAM (or Random Access Memory) 24;    -   an I/O interface 25 for reception of data to transmit, from an        application; and    -   a battery 26.

In accordance with an example, the battery 26 is external to the device.In each of mentioned memory, the word «register» used in thespecification can correspond to area of small capacity (some bits) or tovery large area (e.g. a whole program or large amount of received ordecoded data). The ROM 23 comprises at least a program and parameters.The ROM 23 may store algorithms and instructions to perform techniquesin accordance with present principles. When switched on, the CPU 22uploads the program in the RAM and executes the correspondinginstructions.

RAM 24 comprises, in a register, the program executed by the CPU 22 anduploaded after switch on of the device 20, input data in a register,intermediate data in different states of the method in a register, andother variables used for the execution of the method in a register. Theimplementations described herein may be implemented in, for example, amethod or a process, an apparatus, a software program, a data stream, ora signal. Even if only discussed in the context of a single form ofimplementation (for example, discussed only as a method or a device),the implementation of features discussed may also be implemented inother forms (for example a program). An apparatus may be implemented in,for example, appropriate hardware, software, and firmware. The methodsmay be implemented in, for example, an apparatus such as, for example, aprocessor, which refers to processing devices in general, including, forexample, a computer, a microprocessor, an integrated circuit, or aprogrammable logic device. Processors also include communicationdevices, such as, for example, computers, cell phones, portable/personaldigital assistants (“PDAs”), and other devices that facilitatecommunication of information between end-users.

In accordance with an example of device, the multiplex stream MX 1 (FIG.1 ) is obtained from a source. For example, the source belongs to a setcomprising:

-   -   a local memory (23 or 24), e.g. a video memory or a RAM (or        Random Access Memory), a flash memory, a ROM (or Read Only        Memory), a hard disk;    -   a storage interface (25), e.g. an interface with a mass storage,        a RAM, a flash memory, a ROM, an optical disc or a magnetic        support;    -   a communication interface (25), e.g. a wireline interface (for        example a bus interface, a wide area network interface, a local        area network interface) or a wireless interface (such as a IEEE        802.11 interface or a Bluetooth® interface); and    -   an picture capturing circuit (e.g. a sensor such as, for        example, a CCD (or Charge-Coupled Device) or CMOS (or        Complementary Metal-Oxide-Semiconductor)).

In accordance with an example of the device, the remapped pictureREMAP.PICT. (FIG. 1 ) is sent to a destination; specifically, thedestination belongs to a set comprising:

-   -   a local memory (23 or 24), e.g. a video memory or a RAM, a flash        memory, a hard disk;    -   a storage interface (25), e.g. an interface with a mass storage,        a RAM, a flash memory, a ROM, an optical disc or a magnetic        support;    -   a communication interface (25), e.g. a wireline interface (for        example a bus interface (e.g. USB (or Universal Serial Bus)), a        wide area network interface, a local area network interface, a        HDMI (High Definition Multimedia Interface) interface) or a        wireless interface (such as a IEEE 802.11 interface, WiFi ® or a        Bluetooth ® interface);    -   a display 11; and    -   an IRD 10.

In accordance with examples of the device, the signal F carrying thedescriptor HDR DESCR. is obtained from a source. Exemplarily, the signalF is read from a local memory, e.g. a video memory (24), a RAM (24), aROM (23), a flash memory (23) or a hard disk (23). In a variant, thebitstream is received from a storage interface (25), e.g. an interfacewith a mass storage, a RAM, a ROM, a flash memory, an optical disc or amagnetic support and/or received from a communication interface (25),e.g. an interface to a point to point link, a bus, a point to multipointlink or a broadcast network.

In accordance with examples, the device 20 being configured to implementa method described in relation with FIG. 1 , belongs to a setcomprising:

-   -   a mobile device;    -   a communication device;    -   a game device;    -   a tablet (or tablet computer);    -   a laptop;    -   a still picture camera;    -   a video camera;    -   an encoding chip;    -   a still picture server; and    -   a video server (e.g. a broadcast server, a video-on-demand        server or a web server).

FIG. 3 shows an example of the syntax of such a signal F when apacket-based transmission protocol is used. Each transmitted packet Pcomprises a header H and a payload PAYLOAD. A bit of the header H, forexample, represents an additional information indicating the presence ofone particular type of said metadata and if this additional informationis present for the whole duration of the video streams (payloadPAYLOAD).

More precisely, according to an embodiment, and as described in exampleof Table 1, some bits may be reserved and form a HDR metadata descriptorin the transport stream TS packet of the multiplex of FIG. 4 (Multi-plex0 or Multi-plex 1). These bits are flags indicating the presence ofdifferent types of HDR metadata, and indicating if they are present forthe whole duration of the elementary streams 42.

Implementations of the various processes and features described hereinmay be embodied in a variety of different equipment or applications.Examples of such equipment include an encoder, a decoder, apost-processor processing output from a decoder, a pre-processorproviding input to an encoder, a video coder, a video decoder, a videocodec, a web server, a set-top box, a laptop, a personal computer, acell phone, a PDA, and any other device for processing a picture or avideo or other communication devices. As should be clear, the equipmentmay be mobile and even installed in a mobile vehicle.

Additionally, the methods may be implemented by instructions beingperformed by a processor, and such instructions (and/or data valuesproduced by an implementation) may be stored on a computer readablestorage medium. A computer readable storage medium can take the form ofa computer readable program product embodied in one or more computerreadable medium(s) and having computer readable program code embodiedthereon that is executable by a computer. A computer readable storagemedium as used herein is considered a non-transitory storage mediumgiven the inherent capability to store the information therein as wellas the inherent capability to provide retrieval of the informationtherefrom. A computer readable storage medium can be, for example, butis not limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, or device, or any suitablecombination of the foregoing. It is to be appreciated that thefollowing, while providing more specific examples of computer readablestorage mediums to which the present principles can be applied, ismerely an illustrative and not exhaustive listing as is readilyappreciated by one of ordinary skill in the art: a portable computerdiskette; a hard disk; a read-only memory (ROM); an erasableprogrammable read-only memory (EPROM or Flash memory); a portablecompact disc read-only memory (CD-ROM); an optical storage device; amagnetic storage device; or any suitable combination of the foregoing.

The instructions may form an application program tangibly embodied on aprocessor-readable medium.

Instructions may be, for example, in hardware, firmware, software, or acombination. Instructions may be found in, for example, an operatingsystem, a separate application, or a combination of the two. A processormay be characterized, therefore, as, for example, both a deviceconfigured to carry out a process and a device that includes aprocessor-readable medium (such as a storage device) having instructionsfor carrying out a process. Further, a processor-readable medium maystore, in addition to or in lieu of instructions, data values producedby an implementation.

As will be evident to one of skill in the art, implementations mayproduce a variety of signals formatted to carry information that may be,for example, stored or transmitted. The information may include, forexample, instructions for performing a method, or data produced by oneof the described implementations. For example, a signal may be formattedto carry as data the rules for writing or reading the syntax of adescribed example of the present principles, or to carry as data theactual syntax-values written by a described example of the presentprinciples. Such a signal may be formatted, for example, as anelectromagnetic wave (for example, using a radio frequency portion ofspectrum) or as a baseband signal. The formatting may include, forexample, encoding a data stream and modulating a carrier with theencoded data stream. The information that the signal carries may be, forexample, analog or digital information. The signal may be transmittedover a variety of different wired or wireless links, as is known. Thesignal may be stored on a processor-readable medium.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made. For example,elements of different implementations may be combined, supplemented,modified, or removed to produce other implementations. Additionally, oneof ordinary skill will understand that other structures and processesmay be substituted for those disclosed and the resulting implementationswill perform at least substantially the same function(s), in at leastsubstantially the same way(s), to achieve at least substantially thesame result(s) as the implementations disclosed. Accordingly, these andother implementations are contemplated by this application.

The invention claimed is:
 1. A method for adapting a video content tocharacteristics of a display, the method comprising: receiving videodata comprising a transport layer and at least one encapsulated videoelementary stream; obtaining, from the transport layer, additionalinformation descriptive of High Dynamic Range (HDR) properties of the atleast one encapsulated video elementary stream, wherein the additionalinformation comprises parameters descriptive of color primaries,transfer characteristics, and matrix coefficients; obtaining displaydescription data comprising the characteristics of the display, whereinthe characteristics comprise one or more formats supported by thedisplay; based on the additional information and the display descriptiondata, determining whether the video content is displayable on thedisplay; and in response to determining that the video content isdisplayable on the display: obtaining the video content by decoding theat least one encapsulated elementary stream; and adapting the decodedvideo content using a content adaptation process selected based on theadditional information and the display description data, wherein thecontent adaptation process comprises color remapping based on dynamicmetadata according to a refresh rate; wherein the additional informationfurther comprises information descriptive of the refresh rate of thedynamic metadata.
 2. The method of claim 1, wherein the additionalinformation is obtainable without decoding the video content from anelementary stream that is encapsulated in the transport stream.
 3. Themethod of claim 1, wherein the video content is encoded in an elementarystream.
 4. The method of claim 1, wherein the additional information ispresent for a whole duration of the video content.
 5. The method ofclaim 1, wherein the additional information indicates that theencapsulated video elementary stream includes dynamic HDR m etadata. 6.The method of claim 5, wherein the additional information comprises afirst refresh information belonging to the group comprising: a maximaldynamic metadata refresh rate; a minimal time interval after which thedynamic metadata will be refreshed.
 7. The method of claim 5, whereinthe additional information comprises a second refresh informationbelonging to the group comprising: a minimal dynamic metadata refreshrate; a maximal time interval after which the dynamic metadata will berefreshed.
 8. A device for adapting a video content to characteristicsof a display, wherein the device comprises a processor configured to:receive video data comprising a transport layer and at least oneencapsulated video elementary stream; obtain, from the transport layer,additional information descriptive of High Dynamic Range (HDR)properties of the at least one encapsulated video elementary stream, theadditional information comprising parameters descriptive of colorprimaries, transfer characteristics, and matrix coefficients; obtaindisplay description data comprising the characteristics of the display,wherein the characteristics comprise one or more formats supported bythe display; based on the additional information and the displaydescription data, determine whether the video content is displayable onthe display; and in response to determining that the video content isdisplayable on the display: obtain the video content by decoding the atleast one encapsulated elementary stream; and adapt the decoded videocontent using a content adaptation process selected based on theadditional information and the display description data, wherein thecontent adaptation process comprises color remapping based on dynamicmetadata according to a refresh rate; wherein the additional informationfurther comprises information descriptive of the refresh rate of thedynamic metadata.
 9. The device of claim 8, wherein the determiningoccurs before starting to decode the video content.
 10. The device ofclaim 8, wherein the additional information is present for a wholeduration of the video content.
 11. The device of claim 8, wherein theadditional information comprises a first refresh information belongingto the group comprising: a maximal dynamic metadata refresh rate; and aminimal time interval after which the dynamic metadata will berefreshed.
 12. The device of claim 8, wherein the additional informationcomprises a second refresh information belonging to the groupcomprising: a minimal dynamic metadata refresh rate; and a maximal timeinterval after which the dynamic metadata will be refreshed.
 13. Anon-transitory storage medium carrying instructions of program code forexecuting a method for adapting a video content to characteristics of adisplay, wherein the method comprises: receiving video data comprising atransport layer and at least one encapsulated video elementary stream;obtaining, from the transport layer, additional information descriptiveof High Dynamic Range (HDR) properties of the at least one encapsulatedvideo elementary stream, the additional information comprisingparameters descriptive of color primaries, transfer characteristics, andmatrix coefficients; obtaining display description data comprising thecharacteristics of the display, wherein the characteristics comprise oneor more formats supported by the display; based on the additionalinformation and the display description data, determining whether thevideo content is displayable on the display; and in response todetermining that the video content is displayable on the display:obtaining the video content by decoding the at least one encapsulatedelementary stream; and adapting the decoded video content using acontent adaptation process selected based on the additional informationand the display description data, wherein the content adaptation processcomprises color remapping based on dynamic metadata according to arefresh rate; wherein the additional information further comprisesinformation descriptive of the refresh rate of the dynamic metadata. 14.The non-transitory storage medium of claim 13, wherein the additionalinformation comprises a first refresh information belonging to the groupcomprising: a maximal dynamic metadata refresh rate; a minimal timeinterval after which the dynamic metadata will be refreshed.
 15. Thenon-transitory storage medium of claim 13, wherein the additionalinformation comprises a second refresh information belonging to thegroup comprising: a minimal dynamic metadata refresh rate; a maximaltime interval after which the dynamic metadata will be refreshed.